Ethan Couch, who is now 20, has almost fulfilled a 720-day sentence for violating his original probation. He was convicted of killing four people in a drunken driving accident in 2013 when he plowed a pickup truck into a group of good Samaritans helping a stranded driver.

A psychologist testifying for the defense suggested Ethan suffered from "affluenza," a term supposedly meant to indicate that because of a wealthy, affluent upbringing devoid of consequences, he wasn't capable of knowing right from wrong, or fully accepting responsibility.

Juvenile Judge Jean Boyd eventually sentenced Couch to rehab and 10 years of probation.

"As far as any other cases I've dealt with, he's in a class by himself," said Richard Alpert, a former DWI prosecutor in Tarrant County who went up against Couch in juvenile court.